Numerous types of electrodes are typically used in a variety of diverse applications. Electrode structure and characteristics are usually dependent on the application of the electrode.
One type of electrode of the background art comprises a non-conductive substrate layer, such as a polyester layer with an insoluble electroactive material coated on at least one side. Electrical contacts must be placed on the same side as the insoluble electroactive material, resulting in non-symmetrical current distribution. However, non-symmetrical current distribution is not desirable in for example transdermal delivery systems. In such systems, if the current is not uniform, drug delivery may not be uniform and a concentrated current at one electrode point can cause burning and/or irritation of the skin.
In applications of transdermal delivery systems, wherein a high delivery rate is desired, it is also advantageous to have an active electrode with a high capacity. Further, in a transdermal delivery system, wherein released electroactive material ions are to be delivered and used for treatment, electrode high capacity is preferred.
An accepted method of producing thin and flexible electrodes is using conductive vinyl web. However, vinyl web has relatively high sheet resistance and when an active electrode is not regular in shape and size, there is significant differences in the resistance along the length of the electrode, resulting in uneven current distribution.
There is thus a recognized need for, and it would be highly advantageous to have, an electrode, which can provide, uniform and high current density (current distribution) and which has properties of low sheet resistance and high capacity. Still further it would be advantageous to have a method of producing an electrode with low sheet resistance, high capacity and uniform current distribution.